Railway-traffic-controlling apparatus



' Aug. 9, 1927. 1,638,178

H. A. WALLACE RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Nov. 4, 1924 2Sheets-Sheet 1 g g A bq N FE INVENTQR.

' la-W 2 Sheets-sneer. 2

A. WALLACE v Filed Nov. 4. 1924 INVENTOR Z W a H RAILWAY- TRAFFICCONTROLLING APPARATUS Aug. 9, 1927.

M U W Ww kw v Mm N h E Q 98 m H mwv W aN E mw v WM. 7 kw\ MW Mum. v M.\Q ww Q W wYW Patented Aug. 9, 1927.

UNITED STATES PATENT OFFICE. v

HERBERT A. WALLACE, OF EDGEWOOD BOROUGH, PENNSYLVANIA, ASSIGNOR TO THEUNION SWITCH & SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

RAILWAY-TRAFFIC-CONTROLLING APPARATUS.

Application filed November 4, 1924. Serial No. 747,705.

My invention relates to railway trafiic controlling apparatus, such asapparatus of the type wherein governing mechanism on a car or train iscontrolled from the trackway, or apparatus of the type wherein waysidesignals alone are used to govern the speed of cars or trains.

In apparatus of both types it has been proposed to limit the speed oftrains through a territory containing a permanent or temporary hazard,such as a curve, bridge, tunnel, track repairs, etc., which territorymay, for convenience, be termed restricted speed territory. Under suchcircumstances it has been customary to continue the speed restrictionimposed in such territory for a distance in advance of the exit end ofthe territory at least equal to the longest train. This results in aloss of time for shorter trains, however, because obviously it is safeto remove the speed restriction as soon as the rear end of the trainpasses out of the re stricted speed territory.

One object of my invention is the provision, in combination withrestricted speed territory provided with means, such as signals or otherdevices, for limiting the speed of trains, of means for removing suchspeed limitation when the rear end of the train passes out of therestricted speed territory.

I will describe several forms of apparatus embodying my invention, andwill then point out the novel features thereof in claims.

In the accompanying drawings, Fig. 1 is a diagramatic view showing oneform of apparatus embodying my invention for imposing a low speed limitthrough restricted territory and for removing such low speed limit whenthe rear of the train leaves the restricted territory, the speed limitbeing ac:- complished by means of train carried governing mechanismcontrolled from the track way. Fig. 2 is a diagrammatic view alsoembodying my invention and showing means for imposing an intermediatespeed limit through restricted territory and for removing suchintermediate speed limit when the rear of the train leaves therestricted territory, the speed limitin this instance being;

also accomplished by train carried governing mechanism controlled fromthe trackwa-y. Figs. 3 and 4 are diagramatic views showing two differentforms of apparatus,

involving wayside signals only, for impos- 1 ing a speed limitationthrough restricted territory and removing such limitation whencharacters 1 and 1 designate the track rails of a stretch of rallwaytrack along which trallic normally moves in the direction indicated bythe arrow. This stretch of track comprises a restricted speed territoryA-B and an unrestricted speed territory B C.

As here shown, the reason for the restriction in territory A 13 is aswitch D for admitting trains to section A-B from a track D. In the formshown in the present application, the restricted speed territory ABcomprises only one section of track, but such territory may comprise asmany sections as desired. Only one track section of the unrestrictedterritory is shown in the drawing, but it is understood that suchterritory may comprise any suitable number of such sections. The tracksections are electrically isolated by means of insulated joints 2.

Referring first to the unrestricted terri tory, the track section BC isprovided with train governing apparatus, which is as follows:

The section BC is provided with a track circuit comprising a transformerE the secondary of which is connected across the rails at the exit endof the section, and a track relay F connected across the rails at theentrance end of the section. The primary of transformer E is constantlysupplied with alternating current from the secondary of a linetransformer G,'and the primary of the latter transformer is in turnsupplied with alternating current from a source not shown in thedrawing.

.anc'e 3 is connected across the rails at the en.-

trance end of the section, a second impedance 4 is connected across therails at an intermediate point in the section, and a third impedanc'e 5is connected across the rails at the exit end of the section. Loopcurrent is sup; plied by a transformerlil the of which is at timesfurnished with alternating current, as hereinafter explained. When trackrelay F for the section nest in advance of section BC is energized, theloop circuit for section BC passes from the secondary of transformer Hthrough wire 6, front point of contact f relay F wire 8 to the middlepoint of impedance 5, thence through the rails 1 and 1 in multiple toimpedance 3, and from the middle point of the latter impedance throughwire 9, front point of contact 10 of relay F and wire 11 to thesecondary of transforn'ier H The current which is thus supplied to theloop circuit is of what I will. term normaP relative polarity, and itwill be noted that this current is supplied to the section throughoutits length. Vihen track relay F is decnergized, the loop circuit forsection BC passes tom the secondary of transformer H through wire 6,back point of contact 7 of relay F wire 9, impedance 3, track rails 1and 1 in multiple to impedance 1, and from the middle point of thelatter impedance, through wire 12, back point of contact 10 of relay Fand wire 11 to the secondary of transfomer H The current which is thussupplied to the loop circuitis of what I will term reverse relativepolarity, and it will be noted that this current flows in the trackrails between impedances 3 and 4 only.

he train governing apparatus thus far described, is designed forcooperation with train carried speed governing mechanism in thefollowing manner: When track circuit current and loop current of normalrelative polarity are present, a proceed indication is given on thetrain and the train may then travel at a maximum speed or less withoutreceiving an automatic application of the brakes. This maximum speedmay, for 6X- ample, be 65 miles per hour. When loop current of reverserelative polarity and track circuit current are both present, a cautionindication is given aboard the train and the brakes will be applied ifthe speed exceeds a given intermediate value, such, for example, as 35miles per hour. Vfhen either track circuit current or loop current isabsent, a stop indication is given on the train and the brakes will beapplied, if the train exceeds a given low value, such as 15 miles perhour. One form of train carried apparatus which will operate in thismanner is illustrated and pising a track transformer E and a track relaybut this territory is not provided -with a loop circuit, The primary oftransformer E is constantly suppliedqvith current from t-heseconday of aline transformer G, the circuit for this supply heing from the secondaryof transformer G through wires 13 and 19, primary of transformer E andwires 20*and 18 to the secondary of transformer G Owing to the absenceofa ioop circuit in section A B, it-follows that a train passing throughthis territory will receive a stop indication and its'bralces will beapplied if the speed of the train exceeds miles per hour. I

he supply of loop circuit current to section 15-0 is controlled by trackrelay F in the restricted speed territory AB. As here shown, thiscontrol iseffected through the primary of transformer H the circuit forwhichprimary is from the secondary of transformer G through wires 13 and14, contact 15 of relay F wire 16, primary of transformer H wires 17 and18, to the sec-- ondary of transformer G It follows from the foregoing,that as long as track relay F is de-energized, no loop current isfurnished to the rails of section BC, but'that when relay F isenergized, loop current is always furnished to the rails of this sectionsubject, however, to control by traffic conditions in advance of thesection through the medium of track relay F While a train occupies therestricted speed territory A-B, the relay F is open, and this relayremains open until the rear end of the train passes point B. As soon asthis occurs, that is, as soon as track relay F closes, the speedrestriction is removed and the train may then proceed under whateverspeed restriction is imposed in section B@ due to trafiic conditions inadvance of this section. In other words, re 'ardless of the length ofthe train, the permanent, speed restriction is always removed as soonthe rear end of the train leaves the restricted speed territory. 7

Referring now to Fig. 2, I will assume that the characteristics of therestricted speed territoryA B in this view are such that theintermediate speed of 35 miles per hour is safe. This territory isaccordingly provided with a track circuit as in Fig. 1, and with a loopcircuit which includes the entire territory and is constantly suppliedwith alternating current ofreverse relative polarity. It follows thattrains may proceed tirough this territory at 35 miles per hour or less,but that if the speed of the train Lin exceeds such value the brakeswill be applied.

The loop circuits for section 13-0 in the unrestricted territory, are asfollows: -As suming that relay F is'energized, loop cur rent flows fromthe secondary of transformer H through wire 22, front point of contact23 of relay F wire 24, impedance 5, the track rails 1 and a in multiple,impedance 3, and wire 25 to the secondary of transformer H If relays Fand F are both energized, the circuit for the primary of transformer His from the secondary of a transformer K, through wires 31, 30, 18, 40and 32, primary of transformer H wire 33, front point of contact 34'ofrelay F wire 35, front point of contact36 of relay F and wire 37 to thesecondary of transformer K. The primary of transformer K is constantlysupplied with alternating current from the line transformer G thecircuit being from the secondary of transformer G through wires 27, 28and 29, primary of transformer K, and wires and 18 to the secondary oftransformer G Under these conditions, that is, with both relays F and Fenergized, current of normal relative polarity issupplied to the loopcircuit for section BC, and so a train occupying the section may proceedat full speed under a proceed indication.

WVhen track relay F C is tie-energized, the circuit hereinbefore tracedfor supplying current to the primary of transformer H9becomes'inefl'ective because, of the opening of the front point ofcontact 34 of relay F The primary circuit for transformer H is then fromthe secondary of transformer G through wires 38 and 39, back point ofcontact 34 of relay F wire 33, primary of transformer H and wires 32, 40and 41 to the secondary of transformer G The immediate loop circuit forsection BC now passes from the secondary of transformer H through wire22, back point of contact 23 of relay F wire 26, impedance 4, trackrails 1 and 1 in multiple, impedance 3, and wire25 to the secondary oftransformer H The current now supplied to the primary of transformer His of reverse relative polarity and this loop current is now supplied tothe track rails between impedances 3 and 4 only. It follows that a trainbetween these two impedances will receive a caution indication whereas atrain between impedances 4 and 5 will receive a. stop indication.

If track relay F is de-energized while track relay F is de-energized,the condition of relay F X will have no effect on the loop current insection B-C because the secondary circuit for transformer K is opened atthe front point of contact 34 of relay F If, however, relay F istie-energized while relay F is energized, the secondary circuit fortransformer K is opened at the front point of contact 36 of relay F andthe primary of transformer H is supplied directly from the secondary oftransformer G the circuit passing from the secondary of transformer Gthrough wires 27, 28, 29 and 42, back point of contact 36 of relay Fwire 35, front pointof contact 34 of rela F wire 33, orimary oftransformer H and wires 32, 40 and 18 to thesecondary of transformer GThe current which is thus supplied to the primary of transformer H is ofreverse relative polarity, so that a train in section B-C will receive acaution inclication.

The operation of the apparatus shown in Fig. 2, is as follows: While atrain occupies the restricted speed territory A-B the brakes will beapplied automatically if the speed of the train exceeds 35 miles perhour. Due to the fact that track relay F is open, loop current ofreverse relative polarity is supplied to the rails of section B-C, sothat as the train enters this section the speed restriction will becontinued until the rear end of the train leaves the restricted speedterritory, whereupon relay F will be energized so that loop current ofnormal relative polarity will be supplied to the rails of section B'C,provided, of course, that relay F is energized. In other words, thespeed restriction is removed as soon as the rear end of the train passesout of the restricted speed territory. Referring -now to Fig. 3, theapparatus in the form here shown coniprises wayside signals only for.imposing the desired speed limitations. The stretch of track shown inthe drawing comprises, as before, a restricted speed territory A-B andan unrestricted speed territory BC. The

' restricted speed territory is provided with a track circuit comprisinga track transformer E and a track relay F whereas the section B C,forming the unrestricted speed territory, is provided with a trackcircuit comprising a track transformer C and track relay F The circuitsfor the primaries of the track transformers E and E are the same as inFig. 1.

Located at the entrance end of the unre stricted territory BC is asignal S which is biased to the stop position, but may be moved to thecaution position by virtue of a circuit whichpasses from the secondaryof transformer G through wires 13, 43 and 44, contact 45 of track relayF wire 46, operating mechanism of signal S and wires 47 and 18 to thesecondary of transformer G It will be seen, therefore, that signal Sindicates stop or caution according as section B-C is occupied orunoccupied.

Located at intervals through the section BC are three other signals, S Sand S Each of these signals is biased to the cantion position, but maybe moved to the proill ' caution and proceed.

ceed position by virtue of a: circuit which will now be traced. Thecircuit for signal S is from the secondary of transformer G throughwires 13, 43 and 48, contact 49 of track relay F wire 50, circuitcontroller M operated by signal S for the section in advance of sectionBC, Wire 51, contact 52 of track relay F for the section in advance ofsection B C, wires 53 and 53, operating mechanism of signal S, and wires5a and 18 to the secondary of transformer G The proceed indicationcircuit for signal S is the same as the circuit for signal S up to andinclndingwire 53, and is then through wire 58, operating mechanism ofsignal. S, and wires 56 and 18 to the secondary of transformer G T 1ecircuit for signal S is the same as the circuit for signal S up to andincluding wire 53, from which this cir-.

cuit passes through wire 53, operating mechanism of signal S, and wires58 and 18 to the secondary of transformer G it will be seen that signalsS, S and all indicate caution when track relay F is open, but that thesesignals all indicate proceed when track relay F is closed, provided thatcircuitcontroller M and track relay F are also closed, that is, providedthat the section immediately in advance of section B-C is unoccupied.

The operation of the apparatus shown in Fig. 3 is as follows: When atrain moving in the direction indicated by the arrow enters section A.-B, it opens track-relay F thereby opening the circuits for signals S 8*and S so that these signals all change to the caution indication. Whenthe train enters vsection BC, it opens track relay F, thereby causingsignal S to indicate stop. As the rear end of the train passe out ofsection AB, track relay l5 will close, and if circuit controller M andtrack relay F are then closed, signals S 3* and will move to the proceedposition, there by removing the speed restriction which was imposed uponthe train while in section The distance between signals S and S willpreferably be the length of the shortest train using the railroad, andthe distance between signals S and S will preferably be the length ofthe longest train. In each case, however, the distances between shouldbe slightly greaterthan the train lengths in order to give signals S andS time tochange to their proceed indications and to be observed by thedrivers of the trains. Preferably the distances between signals S" and Sand between signals 8* and S will be equal to the length of one car.

It will be noted that signal S is a twoposition signal indicating stopand caution, whereas each of the intermediate signals S S and S is atwo-position signal indicating Signal S indicates signals only stop andcaution because it is controlled by a track circuit and its least resflctive indication inustbe caution. Signals S S and are not controlledby a track circuit, and, therefore, their most restrictive indicationsmust be caution;

Referring now to Fig. l, the-apparatus shown in this view siinil to thatshown in Fig. 3, except that the intermediate sig nal has been onnttezland sect1on fl3.-G is divided into sub-sections BO,- O-P and P-C, toprovide track circuits for the central of signals S" and Each trackcircuit comprises a track transformer E located at the exit end of thesub section and a track reiz F located at the entrance endof thesub-section, each track transforn'ier being supplied with current froman adjacent line transformer G. Signal S as before, is two-positionsignal indicating stop and caution, and is controlled in the same wayEach signal S and S, howas in Fig. 2).

ever, is a three-position si al'indicat ig slop, caution and proceed. ecaution indication circuit for signal S is from the secondary oftransform-er G through wires'GO and 61, contact 62 of track relay F Wire(fiihoperating mechanism of signal o, and

wires to and to the secondary of trans foriner G". The cautionindication circuit proceed indication for nal 55* up to and includingwire 53, and. it then passes through wire 53, operating mechanism ofsignal S and wir s to, 56 and 18, to the secondary of train 7 When atrain enters the restricted speed territory AB, it opens track relay Fthereby opening the proceed indii cuits for signals S" and S. il hcn thetrain enters section B hit places si nal S at stop, and signals S and Sremain it caution. lV hen the rear end of the train passes out ofsection lit-13, track relay F will close, thereby closing the proceedindication circuits for signals S anc S whereupon: these signals will.then change to the proceed indication, assuming, of course, that circuitcontroller M and relay F are closed, and also assuming that track relaysF and F are closed. If section O-P isoccupiec, signal S will indicatestop; whereas,.if sec-- tion P-C is occupied, signal 8* will indi catestop. The caution indication for each of these signals is, therefor,dependent on on cir lull the traflic conditions within the subsectionassociated with the signal, wherefore the indications given by thesesignals are more complete than the indications given by the signals S 8*and S in Fig. 3.

Although I have herein shown and "described only a few forms ofapparatus embodying my invention, it is understood that various changesand modifications may be made therein within the scope of the appendedclaims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is: i V

1. In combination, a stretch of railway track comprising a restrictedspeed territory provided with speed restricting means. means forrestricting the speed of a train in advance of said territory, and meansfor removing such speed restriction when the rear end of the trainpasses out of said restricted speed territory.

2. In combination, a stretch of railway track comprising a restrictedspeed territory provided with speed restricting means, a track circuitfor at least the exit end of said territory including a traclrrelay, andmeans for restricting the speed of a train leaving said. territory aslong as any part of such train keeps said relay tie-energized.

3. In combination, a stretch of railway track comprising a restrictedspeed territory provided with speed restricting means, an unrestrictedterritory immediately in advance of said restricted speed territory andprovided with apparatus for controlling the speed of; trains inaccordance with trafiic conditions in advance, and means operating aslong as any part of a train occupies said restricted speed territory tocondition said apparatus to impose thesame speed restriction on thetrain as is imposed thereon in said restricted speed territory.

4. In combination, a stretch of railway track comprising a restrictedspeed territory provided with speed restricting means, an unrestrictedspeed territory in advance of said restricted territory and providedwith train governing apparatus controlled by traific conditions inadvance, a track circuit for at least the exitend of said restrictedspeed territory including a track relay, and means operating as long assaid relay is de-energized to condition said apparatus to impose thesame speed restriction as is 1111- posed in said restricted speedterrltory.

5. In combination, a track comprising a restricted speed territoryprovided with speed restricting means, an unrestricted section inadvance of sald restricted speed territory and provided with traingoverning apparatus comprising a loop circuit including the two rails ofthe section in multiple, and means for controlstretch of railway traiiicconditions in advance of said section,

and means controlled by a train entering said section from saidrestricted speed territory for supplying said loop circuit with currentof reverse relative polarity as long as any part of the train is inrestricted speed territory.

7. In combination, a stretch of railway track comprising a restrictedspeed territory provided with speed restricting means, an unrestrictedsection in advance of said restricted speed territory and provided withtrain governing apparatus comprising a loop circuit including the tworails of the section in multiple, means for normally controlling saidloop circuit by tra'h'ic conditions in advance of said section, andmeans controlled by a train entering said section from said restrictedspeed territory for conditioning said loop circuit to impose the samespeed restriction as said means in restricted speed territory as long asany part of the train remains in restricted speed territory;

8. In combination, a stretch of railway track comprising a restrictedspeed territory provided with speed restricting means, and

means for continuing the same speed restriction on a train leaving saidterritory as long as any part of the train remains in such territory.

9. In combination, a section of railway track, train governing apparatusin said section comprising a loop circuit including the two rails of the'section in multiple, means for supplying said loop circuit with currentof normal or reverse relative polarity according to traffic conditionsin advance of said section, and means controlled by a train enteringsaid section for supplying said loop circuit with current of reverserelative polarity regardless of traffic conditions in advance of thesection until the rear of the train enters the section.

10. In combination, a section of railway track, train governingapparatus for said section comprising a loop circuit including the tworails of the section in multiple, means for normally controlling saidloop circuit in accordance with traflic conditions in advance to imposedifferent speed limits on trains in the section, and means controlled bya train entering said section for controlling said loop circuit toimpose a less than maximum speed limit regardless of traflic conditionsin advance of the section until the rear of the train has entered thesection.

11. In combination, a stretch of railway track comprising a restrictedspeed territory and an unrestricted speed territory, and means forcontinuing the speed restriction on a train entering said unrestrictedspeed territory from said restricted speed territory 10 and removingsuch speed restriction when the rear end of the train leaves said restricted speed territory.

In testimony whereof I affix my signature.

HERBERT A. WALLACE.

